Detection Limits For Fe3 Research Articles

Water-soluble rhodamine-based chemosensor for Fe3+ with high sensitivity, selectivity and anti-interference capacity and its imaging application in living cells

Fe3+ plays a crucial role in many vital cell functions and its detection has attracted considerable attention. In this work, a water-soluble rhodamine-based chemosensor RL has been designed and synthesized as an “off-on” chemosensor for Fe3+ detection. Upon the addition of Fe3+, RL displayed obvious color change, quick fluorescence enhancement, high sensitivity and anti-interference capacity over other metal ions (Li+, Na+, K+, Mg2+, Ca2+, Ba2+, Al3+, Sn2+, Pb2+, Bi3+, Cr3+, Mn2+, Co2+, Ni2+, Pd2+, Cu2+, Ag+, Zn2+, Cd2+, Hg2+). The detection limit for Fe3+ was calculated to be 0.28 μM with the binding constant Ka to be 4.67 × 108 M−2. Furthermore, an application of RL in the imaging of HeLa cells exposed to Fe3+ was also successfully demonstrated.

Novel oligothiophene-based dual-mode chemosensor: “Naked-Eye” colorimetric recognition of Hg2+ and sequential off-on fluorescence detection of Fe3+ and Hg2+ in aqueous media and its application in practical samples

A novel oligothiophene-based dual-mode chemosensor A3TA was designed and synthesized for Fe3+ and Hg2+ in aqueous media. The sensor A3TA showed high selectivity and sensitivity toward Fe3+ and Hg2+ over other competitive metal ions. Hg2+ was detected by changing color from khaki to reddish brown, could be easily distinguished by bare eyes. Moreover, the sensor also acted as a “turn-on” type fluorescent sensor toward Fe3+ and Hg2+. The detection limits for Fe3+ and Hg2+ were found to be as low as 3.52×10−8 and 5.0×10−8M, respectively. The stoichiometric ratio of the sensor toward Fe3+/Hg2+ ions was obtained to be 1:2. Furthermore, the proposed sensor A3TA was also found to have high association constants (105M−2), wide pH range (4–12) and short response time (3–5min). In addtion, the sensing mechanism was proposed based on chelation-enhanced fluorescence (CHEF) and investigated in detail by fluorescence spectroscopy, 1H NMR titrations, FT-IR and HRMS spectra analysis. Importantly, the proposed sensor A3TA has been successfully used to quantify trace amounts of Fe3+ and Hg2+ in real samples.

Combining field-amplified sample stacking with moving reaction boundary electrophoresis on a paper chip for the preconcentration and separation of metal ions.

A common drawback of paper-based separation devices is their poor detection limit. In this study, we combined field-amplified sample stacking with moving reaction boundary electrophoresis on a paper chip with six array channels for the parallel separation and concentration of multiple samples. With a new hyphenated technique, the brown I2 from the Fe3+ /I- oxidation-reduction reaction emerged near the boundary between the dilute ethylene diamine tetraacetic acid and potassium iodide and highly concentrated KCl solutions. For the separation and concentration of three components, Cr3+ , Cu2+ , and Fe3+ , the Fe3+ detection limit was improved at least 266-fold by comparing the hyphenated technique with moving reaction boundary electrophoresis. The detection limit of Fe3+ was found to be as low as 0.34 ng (20 μM) on the paper chip. We also demonstrated the analysis of a real sample of four metal ions, with detection limits as follows: 0.16 μg Cr3+ , 1.5 μg Ni2+ , 0.64 μg Cu2+ , and 1.5 μg Co2+ . The synergy of field-amplified sample stacking and moving reaction boundary electrophoresis in the micron paper-based array channels dramatically improved the detection limit and throughput of paper-based electrophoresis.

A Novel Nanofibrous Film Chemosensor for Detecting and Adsorbing Fe3+

A novel nanofibrous film chemosensor was designed and fabricated for detecting Fe3+. It displayed good sensitivity and selectivity as a sensing material for Fe3+. The addition of Fe3+ would induce obvious fluorescent quenching of the nanofibrous film and the other common metal ions did not interfere in the recognition of Fe3+. The detection limit for Fe3+ of this sensing material was calculated to be 10.63 μmol L-1. Moreover, the nanofibrous film could not only be regarded as a chemosensor for detecting Fe3+, but also as an adsorbent to remove Fe3+ with high efficiency in solution. The adsorption capacity was calculated to be 13.93 mg g-1 of Fe3+/nanofibrous film from Langmuir plot.

Europium-doped gadolinium oxide nanoparticles: A potential photoluminescencent probe for highly selective and sensitive detection of Fe3+ and Cr3+ ions

Herein, we report the facile synthesis, characterizations and photoluminescence sensing probe applications of europium (Eu3+)-doped gadolinium oxide (Gd2O3) nanoparticles. The Eu3+- doped Gd2O3 nanoparticles were synthesized by a facile and straight forward chemical synthesis followed by the calcination process. Various percent concentrations of Eu3+ ranging from 1 to 5% was used to dope into the Gd2O3 and calcine them for different time to optimize the photoluminescence properties of the synthesized nanoparticles. The synthesized nanoparticles were characterized by several techniques which confirmed that the 5% Eu3+- doped Gd2O3 nanoparticles exhibited best structural and optical properties. Thus, due to best structural and optical properties, the 5% Eu3+- doped Gd2O3 nanoparticles were used as photoluminescent probe for the detection of Fe3+ and Cr3+ ions. The detailed sensing results revealed that the synthesized nanoparticles are quite selective and sensitive towards Fe3+ and Cr3+ ions with 99.3% quenching efficiency for 10ppm Fe3+ ions and 98.6% quenching efficiency for 40ppm Cr3+ ions respectively. The detection limit for Fe3+ and Cr3+ ions were 1.48ppm and 6.56ppm respectively. The utilization of synthesized nanoparticles in real water samples with percentage recovery of >90% in tap water and distilled water and 87% in sewage water has unlocked numerous opening to use such nanomaterial for real water treatment applications.

Synthesis and evaluation of a novel rhodamine B-based ‘off-on’ fluorescent chemosensor for the selective determination of Fe3+ ions

A new rhodamine B derivative, namely, N1-(benzo[d]thiazol-2-yl)-N4-(2-(3′,6′-bis (diethylamino)-3-oxospiro[isoindoline-1,9′-xanthen]-2-yl)ethyl)malea-mide (RDBSF), was designed, synthesized, and structurally characterized to develop a new chemosensor. UV–vis absorption and fluorescence spectroscopic studies show that RDBSF exhibits high sensitivity and selectivity toward Fe3+ in the presence of many other metal cations in a Tris-HCl solution (1mM, pH=7.4) containing 30% MeCN by forming a 1:1 complex with Fe3+. The binding association constant (Ka) of RDBSF for Fe3+ was estimated as 1.52×104M−1 in the solution. The detection limit of Fe3+ by RDBSF was further determined as 11.6nM. Intracellular imaging applications demonstrated that RDBSF can be used as a fluorescent probe for the detection of Fe3+ in HepG-2 cells.

An unusual “off-on” fluorescence sensor for iron(III) detection based on fluorescein–reduced graphene oxide functionalized with polyethyleneimine

Polyethyleneimine (PEI)–modified reduced graphene oxide (rGO) based fluorescent sensor is reported for metal-ion sensing. PEI–rGO nanocomposites are synthesized by a facile and controllable method using hydrazine hydrate as a main reducing agent and PEI that is a reducing agent, surface modifier and polymer host. The formation of PEI–rGO nanocomposites is confirmed with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV–vis spectroscopy, Zeta potential measurements and Dynamic Light Scattering (DLS) analysis. Afterward, the interaction of fluorescein (FL) with PEI–rGO nanocomposites in aqueous dispersion, leading to the formation of FL/PEI–rGO ternary system, are studied at various conditions by using UV–vis absorption, steady-state and time-resolved fluorescence spectroscopies. It is observed that the photophysical properties of FL are dependent on the amount of both FL and PEI–rGO nanocomposites. The sensing ability of FL/PEI–rGO ternary system are examined in the detection of metal ions as a fluorescent sensor. The spectroscopic data reveal that the FL/PEI–rGO ternary system shows high sensitivity and selectivity for Fe3+ ions in aqueous solution. The detection limit for Fe3+ are determined to be 1.12μM.

A single optical sensor with high sensitivity for detection of Fe3+ and CN− ions

1,2-Bis(2-hydroxymethylphenoxy)ethane was synthesized and characterized by FT-IR and 1H NMR spectroscopy, and single crystal X-ray diffraction method. The sensing ability of the sensor was studied in the presence of different cations and anions. Following the excitation wavelengths at 275nm in EtOH/H2O (1:9, v/v) and 310nm in MeCN/H2O (1:9, v/v), two distinct emissions at 305 and 356nm were obtained, respectively. Fe3+ and CN− ions were successfully detected in EtOH/H2O and MeCN/H2O mixtures, respectively. While the fluorescence intensity of the sensor quenched considerably in the presence of Fe3+ cation at 305nm, it enhanced in the presence of CN− anion at 356nm. Selectivity of the sensor toward these ions was verified in the presence of a variety of common interfering ions. The detection limits of Fe3+ and CN− were calculated as 5.4 × 10−9molL−1 and 1.9 × 10−8molL−1, respectively which shows the high sensitivity of the sensor toward the target ions. Finally, the interaction of the sensor and CN− anion was determined by computational studies.

Solvatochromic shift and estimation of dipole moment of synthesized coumarin derivative: Application as sensor for fluorogenic recognition of Fe3 + and Cu2 + ions in aqueous solution

(S)-4-((4-((3-amino-2-oxo-4-phenylbutoxy)methyl)-1H-1,2,3-triazol-1-yl)methyl)-7 hydroxy-2H-chromen-2-one hydrochloride was synthesized and characterized by detailed spectroscopic studies such as 1H, 13C NMR and HRMS. Excited state dipole moment of synthesized compound was obtained using different solvatochromic shift methods. High value of dipole moment is observed for excited state as compared to ground state value and this is attributed to more polar excited state of molecule. Also, fluorescence emission peak undergoes a bathochromic shift with increase in the polarity of the solvent, confirming π→π* transition. The potential sensor behavior of the compound to metal ions has also been examined. Chemosensor shows the sensitivity for Fe3+ and Cu2+ over other metal cations in aqueous solution. The detection limits of Fe3+ and Cu2+ were calculated to be 143nM and 71.31μM, respectively. The LC–mass analysis indicated that 1:1 complex was formed between Fe3+ (or) Cu2+ and compound. Binding energy values for the complexation of the compound with metal ions are theoretically computed at M06/6–31+G(d,p) level. The DFT based binding energy values show good correlation with the experimental observations.

A ratiometric fluorescent probe for ferric ion based on a 2,2′-bithiazole derivative and its biological applications

A new bithiazole-based ratiometric fluorescent chemosensor 4,4′-n-butyl-5,5′-(pyridin-4-yl)-2,2′-bithiazol (L) is prepared and its metal ion sensing properties have been investigated. It exhibits high sensitivity and selectivity toward Fe3+ among a series of metal ions in EtOH: H2O (9:1, v/v). The probe displays a quick response for Fe3+ over a broad pH range, and the presence of Fe2+ can also be detected by adding an oxidant like Na2O2 or H2O2. The association constant of resultant [FeL2] cation is calculated to be 2.76×103M−2, and the detection limit for Fe3+ is found to be 0.6μM. The living cell and zebrafish imaging experiments demonstrate its value on the practical applications for biological systems.

Image based kinetic determination of iron(III) in blood samples using a CCD camera

Digital image-based calibration was applied for the determination of iron(III), Fe3+, as a catalyst in the oxidation of indigo carmine (IC) using bromate ion (BrO3−). During the reaction, a colorless product was produced and there was an induction period (IP) before the color of the solution faded. The length of IP depended on the concentration of Fe3+. The color fading of reaction was recorded as a change of red, blue and green colors (%RBG). Kinetic profiles similar to what has been reported in a previous spectrophotometric study were obtained. Fe3+ was determined in the concentration range of 6–16 ppm at pH = 2 and 25 °C. The detection limit of Fe3+ was found to be 1.994 ppm, which is better in comparison with the previous work. Optimum concentrations of IC and BrO3− were obtained as 5.5 × 10−5 and 3 × 10−3 M, respectively, using a one-at-a-time optimization method. The optimum pH value was 2. The interference effect of various cations and anions on the determination of iron is reported. In addition, the application of the method to real samples of human serum was performed. The obtained results from real samples were in accordance with the obtained results using standard methods. The analysis of images (movies) recorded from an evolutionary chemical systems seems to open new, simple and low-cost analytical opportunities.